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Topic: Solar upgrade (Read 8898 times)

I just this past week added to my solar backup system... I now have what I consider an almost workable emergency power system & I would like to offer the specs to anyone here who is thinking about getting into this, but doesn't know where to start. I have doubled my battery bank & almost doubled my panel array. So here's what I have now...

As a test of the system I ran my pellet stove uninterrupted (during the night, so not charging at the time) for 11 hours, until we were too hot & had to shut it down. At the time of shut down the batteries were depleted to 11.8 volts, so I likely would get another 3 or 4 hours out of it. This is pretty decent as the stove draws a decent load, particularly in start up.

My tips- Use only a pure sine inverter, unless you only want to power a couple of lights. There's a lot of stuff that will not run with modified sine waves.- Get a lot of panels... More than I have. Get twice as much as you think you need. Charging is slow.- Incorporate wind. I can't speak from experience but I've read that they cost more for good reason. A wind turbine may be my next addition.- Use the heaviest wire you can, with the shortest possible run. It seems that every inch of extra wire = power loss.

If I can think of anything else to add, I will. I would love to hear tips, tricks, experiences from anyone else on here!

Use only a pure sine inverter, unless you only want to power a couple of lights. There's a lot of stuff that will not run with modified sine waves.

Pure sine wave is always best because anything will run on it. That said there are grades of "pure sine wave". A Xantrex PROwatt SW 2000 watt "pure sine wave" inverter is a lot less expensive than a Xantrex PROsine, and the quality of the output is a lot lower. The PROsine specifies the distortion, and has tighter tolerances on the output voltage and frequency.

There are many things other than lights that will work fine on "modified sine wave". Any device with a universal power supply that says it can run on anything from 100 to 240 volts without switching, will run just fine on modified sine wave power.

Get a lot of panels... More than I have. Get twice as much as you think you need. Charging is slow.

Yep.

My first two systems had 3 panels each for a total of 55 watts per system. One system runs my CPAP at night and charges my cell phone. The other system runs my ham radio.

Everything was fine all summer, but come winter the system for the CPAP could not keep the battery charged, so I had to supplement the solar charging with an AC powered charger. I have now bought another 55 watt system and put 2 of the new panels on my CPAP system (because that was the limit of the charge controller). So I now have 91 watts of panel and I am hoping that will get me through the winter without needed extra battery charging.

Incorporate wind. I can't speak from experience but I've read that they cost more for good reason. A wind turbine may be my next addition.

I have a friend with a (now broken) wind turbine. He tells me it is very hard to size them so they produce useful power at a given location. He found that his turbine produced useful power only on rare occasions because most of the time the wind was either too slow or two fast.

The manufacturer of his turbine went out of business, then the bearings died and trashed the windings of the turbine. The cost to repair was very close to the new cost so he has not had it repaired.

Use the heaviest wire you can, with the shortest possible run. It seems that every inch of extra wire = power loss.

True, but this is most critical in the high current parts of the system. My solar panels came with very thin wire, and I replaced the long run into the charge controller with 10 gauge speaker wire. For my battery bank I connected the batteries together with the heaviest gauge (lower number) battery wires I could buy at Walmart, and did the same to connect the batteries to the big inverter.

Suburban; your experiences & observations are very much appreciated! I have spent some time today looking into how to build a wind turbine... Sounds easy, provided one selects the correct motor! We will see if it actually happens, lol.

True, but this is most critical in the high current parts of the system. My solar panels came with very thin wire, and I replaced the long run into the charge controller with 10 gauge speaker wire. For my battery bank I connected the batteries together with the heaviest gauge (lower number) battery wires I could buy at Walmart, and did the same to connect the batteries to the big inverter.

For 3 days now I have been trying to recharge my bank. It's been very overcast & my batteries are only up to about 12.2... So I have got to get more panels!!! I figure that the watts should equal the amp hours, like in Bill's setup... I'm no where near there.

I figure that the watts should equal the amp hours, like in Bill's setup...

That's been my rule of thumb when constructing this system.

If I could, I'd increase the ratio of watts to amp hr battery storage even more, given that my location endures a lot of fog and overcast, especially during the rainy season. OTOH, when we do get sunlight, it's generally very clear and bright. 1200 watts of solar panels could bring my batteries from 50% to full in four hours or so. And my projected usage would drop the bank from full to half over a period of two weeks. Even in the worst of weather, we'll generally get at least one good, sunny day in any given two week period.

Another thing: I've never seen prices as low as right now on solar panels.

Check out sunelec.com, where I bought most of mine.

You can buy a pallet (22) of 280 watt panels for .89/watt. They say they'll break it up, but recommend buying an entire pallet and sharing with friends. I'm considering trying to put something like that together, if there is any interest around here. I'd want three for myself, leaving 19 for anybody else who was interested in a deal like this.

Another thing: I've never seen prices as low as right now on solar panels.

Check out sunelec.com, where I bought most of mine.

You can buy a pallet (22) of 280 watt panels for .89/watt. They say they'll break it up, but recommend buying an entire pallet and sharing with friends. I'm considering trying to put something like that together, if there is any interest around here. I'd want three for myself, leaving 19 for anybody else who was interested in a deal like this.